Typical hydraulic pump systems include a hydraulic pump that pumps and/or cycles fluid to a hydraulic device to do work (for example, to drive a hydraulic motor of a vehicle or to drive a hydraulic suspension system of a vehicle). In the operation of hydraulic pumps, a substantially continuous supply of fluid to the hydraulic pump is desired to minimize or prevent cavitation (i.e., interruptions of fluid supply to the hydraulic pump) within the hydraulic pump, which may damage or decrease the efficiency of the hydraulic pump. Hydraulic systems also typically lose fluid due to evaporation, leaks, and/or inefficiencies that further increases the risk of an interruption of fluid supply to the hydraulic pump. To overcome these issues, hydraulic systems typically include a fluid reservoir with additional fluid that compensates for fluid loss within the system. However, drawing fluid from a reservoir may not be sufficient to supply uninterrupted fluid supply for hydraulic pumps, in particular, for high speed hydraulic pumps that may be used in hydraulic vehicles or hydraulic suspension systems that require substantially fast response time of the hydraulic circuit. Additionally, some hydraulic pumps may operate better when the fluid entering the hydraulic pump is at a pressure that is higher than atmospheric. To provide a substantially continuous supply of pressurized fluid to a hydraulic pump also serves as a challenge. Some hydraulic systems in the field utilize low pressure supercharge pumps to increase the pressure/aid the flow of fluid to the hydraulic pump. However, such supercharge pumps may not be fast enough to provide enough fluid at the desired pressure under high speed conditions. Alternatively, large supercharge pumps may be utilized, but such large supercharge pumps may be expensive and costly to operate. In other hydraulic systems, a low pressure accumulator may be used to “store” fluid at an increased pressure that is readily available to the hydraulic pump when necessary. However, hydraulic systems that utilize such low pressure accumulators must maintain a certain volume of pressurized fluid within the low pressure accumulator and may include a system dedicated to maintaining the low pressure accumulator, which may be substantially costly, complicated to manage and maintain, and consume a substantially large amount of energy. In systems that aim to utilize hydraulic power as a means to replace fossil fuels, using such methods to main low pressure accumulators may not be an attractive option.
Thus, there is a need in the hydraulic pump field to create an improved hydraulic system with a low pressure accumulator that provides a substantially continuous supply of fluid for a hydraulic pump.